<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>固定的底栏</title>
    <style>
        body{
            margin: 0;
            padding: 0;
        }
        section {
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        header {
            height: 50px;
            background-color: #77BBDD;
        }

        footer {
            height: 120px;
            background-color: #666666;
        }

        .content{
            flex: 1;
            background-color: #e4e0db;
        }
    </style>
</head>
<body>
<section>
    <header></header>
    <div class="content"></div>
    <footer></footer>
</section>
</body>
</html>